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Why do some people have a blue string among their tzitzit fringes?

Why do some people have a blue string among their tzitzit fringes?


We read in the Torah:1 “Speak to the children of Israel and you shall say to them that they shall make for themselves fringes (tzitzit) on the corners of their garments, throughout their generations, and that they shall affix a thread of techelet on the fringe of each corner.”

The verse contains two commandments. One is to affix (white) fringes on the corners of a four-cornered garment, and the other is to add a thread of techelet to each corner. These two commandments are independent of each other. When techelet is available, we are enjoined to add a techelet fringe to the tzitzit; when unavailable, we fulfill the mitzvah with plain white fringes.

Techelet is wool dyed with blood extracted from a sea animal called the chilazon.

So why is it not so common today to have a techelet fringe on the tallit or tzitzit? At a certain point in history, approximately 1000 years ago, the chilazon, which was always hard to come by—to the extent that the Talmud2 tells us that it surfaced only once every seventy years—became unavailable altogether. After a while, its exact identity became unknown.

There have been many who have tried to rediscover the identity of the chilazon. Most notable among them were the Radziner rebbe, Rabbi Gershon Henoch Leiner (1839–1891), and Israeli Chief Rabbi Y. I. Herzog (1888–1959).

Rabbi Leiner maintained that the cuttlefish was the lost chilazon, and proceeded to produce and distribute dye produced from this fish.

Recently, the marine snail Murex trunculus has been identified as possibly being the elusive chilazon, and many use its dye.

Many, however, view the findings of these groups as uncertain. In addition, the kabbalists write that our current lack of techelet is consistent with our diminished spiritual state.3 As such, most continue to wear only white fringes, awaiting the coming of Moshiach, when Elijah himself will guide us in uncovering the identity of the chilazon.

Yours truly,
Rabbi Menachem Posner

Rabbi Menachem Posner serves as staff editor for
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Discussion (22)
June 1, 2016
blue tread
We have modern technology, so why can't we just use a normal blue tread. Yes at that time there were no factories or places to just buy or make blue, but now we can so why not do it to keep the mitzvah
June 11, 2015
The tekhelet (biblical blue dye) made from the murex trunculus snail has to be the real tekhelet because: it mentions in the talmud that there was only 2 ways to make blue dye, the first way was using the chilazon (animal which tekhelet is produced). And the second way was using the indigo flower (a much more affordable way). It says that tekhelet is only valid if produced with the chilazon, and if you use the indigo flower it is not fit for use, people wanted to use the indigo flower because it was much cheaper.

The Talmud states that argaman (an ancient purple color that the Romans liked to use (the Romans called it Tyrian purple) was also produced using the chilazon. and recently historians stated that the murex trunculus snail was used for dye in ancient times based on their findings: they found a pit in Tyre (southern Lebanon) which was filled with murex trunculus snail shells, and in old hebrew Tyre is referred to as tzor, and it mentions that the chilazon was caught in the area between tzor and haifa! and other historians found a fabric which was blue, and they tested this fabric and the tests showed that it was dyed using the murex trunculus snail! So this proves that the murex trunculus snail dye is the true tekhelet.
Dovid aryeh Rapoport
December 29, 2014
Eithopians Too
The Ethiopian Jews, who are now well established in Israel, also commonly have white clothes. Particularly amongst their women does one see the use of large enwrapping "shawls" having a thick blue stripe along two edges. This tradition may date from before the time when the Jews became Jews (and we were still regarded as Hebrews or Bnai-Yisrael), because the Ethiopians come from the first Assyrian dispersion, that is before the return from Babylon and the formalization of our present religion.
David Chester
Petach Tikva, Israel
December 28, 2014
I think the symbolism of the blue thread is beautiful and poignant.

Simple question: does it render the tzizis un kosher by having a blue thread in it, regardless of the source of the dye?
Isaac HaLevi
July 24, 2013
I read somewhere the process of getting the blue from the snail is done while it is alive, so this renders it kosher. I can't remember where I read it though.
February 20, 2013
To Gershon
Hmmm. I think you have an interesting point regarding the donkey...don't think we chopped off his head though. As I understand it, the donkey is the only unkosher animal to have kedusha, holiness, and thus, the first born had to be redeemed. That means a lamb gets sacrificed. If the donkey is not redeemed, then someone breaks his neck. Ouch! God, do You really want us to do that? That aside...
The rumor is the donkey gets kedusha status for helping us get out of town, that is, Egypt. And then shlepping all our supplies for 40 years in the desert without complaint, unlike our ancestors that kvetched all the time.
As far as other dyes in the Temple coming from unkosher sources, well, it doesn't say so in the Torah as far as I know.
If that was passed down in the Oral Law, well, one of the hazards of playing telephone as kids, the message gets messed up. And that's how the poor unkosher snail got crushed in all this.
February 20, 2013
To Marty
I think that some of the other dyes used for the Temple were also made of unkosher sources. Think also of the firstborn donkey whose head was to be chopped off.
February 19, 2013
sky blue works
Are there any other times in the Tanach or the Talmud where we're required to use something from an unkosher animal? If not, then we've probably been wrong using snails all along.
I think God is scratching His head wondering why all the meshugas, "I just thought if you had a blue thread you'll remember the commandments comes from heaven, and that I am watching what you do."
So, Nu, any plant or artificial dye will do.
February 19, 2013
techelet: blue tests
Rabbi Yisroel Lipschutz: tests in the Talmud for the blue dye? What are these tests and what is the source of the source in the Talmud?
Ed Friedman
Silver Spring MD
January 7, 2013
Techeles in Tzitzis....
Marty writes: Rabbi Yisroel Lipschutz, writes in his Kupat HaRochlim (found in his introduction to Seder Moed) that there is no specific requirement to use the extract of the Chilazon. Any blue dye that will stand up to the chemical tests outlined in the Talmud may be used. .
Thank you Marty for sharing this. If Rabbi Lipchutz is correct, [and I have been asking the same question for years] that we may use any artificial dye [that matches the techeles of the Chilazon and I'm sure we can manufacture this colour with the technology of today, why can't we use it in our Tziitzith. Of course, You need a high powered microscope to examine it beyond the physical seeing using a 20 - 20 vision with our eyes.
It all boils down to Toras Hashem and Toras Ha-adam [the many stringencies invented by man.] I heard that some Rabbis are afraid to go against their teachers and state the truth because of what their Rebbe says.
David Aharon Lindzon
Toronto, Ontario Canada